Liquid-fuel injection means for prime movers



Dec. 2, 1952 R. J. [FIELD ET AL LIQUID-FUEL INJECTION MEANS FOR PRIMEMOVERS Filed July 10, 1947 AP/ V .-h- Q Q a a N m l f z/fl mm 0 -v 4 63E A? P u m Patented Dec. 2, 1952 UNITED STATES LIQUID-FUEL INJECTIONMEANS FOR PRIME MOVERS Richard Joseph Ifield and Ernest Ansley Watson,Birmingham, England, assignors to Joseph Lucas Limited, Birmingham,England Application July 10, 1947, Serial No. 760,002 In Great BritainOctober 17, 1941 Section 1, Public Law 690, August 8, 1946 Patentexpires October 17, 1961 Claims.

This invention relates to liquid fuel injection systems for primemovers, and of the kind comprising a pump driven by the prime mover anda delivery nozzle or nozzles to which the fuel is supplied by the pump.When .the prime mover is initially set in motion by an electric motor orother external source of power, the speed of rotation is ofteninsufficient to enable an adequate delivery to be obtained from the pumpto ensure prompt and efiective starting of the prime mover under its ownpower. To meet this condition an auxiliary starting pump has alreadybeen used, but this is not an entirely satisfactory expedient.

The object of the present invention is to provide improved means forproviding an adequate quantity of liquid fuel to the prime mover in thestarting operation.

The invention comprises a system having in combination with the pumpwhich normally supplies the fuel to the prime mover, an accumulatorwhich in the starting operation is first charged by the pump, and whichsubsequently delivers its charge to the nozzle or nozzles, and a valvefor controlling the accumulator outlet.

In the accompanying sheet of explanatory drawings:

Figure l is a diagram illustrating a liquid-fuel injection systemembodying the invention.

Figure 2 is a sectional elevation of the accumulator employed in thesystem illustrated in Figure 1.

Figure 3 is a diagram illustrating a modified form of the invention.

Figure 4 is a sectional elevation of a preferred form of the accumulatorand valve illustrated in Figure 3.

In carrying the invention into effect as shown in Figures 1, and 2, weemploy a hollow cylindrical accumulator a of any suitable capacity.Within this is arranged a piston b which is loaded by an adequate springor springs as 0, weight or gas under pressure. At one end of theaccumulator a is provided an inlet d adapted to be connected to thenormal fuel supply pump e driven by the prime mover (not shown), andalso an outlet 1 adapted to be connected to the delivery nozzle ornozzles as g. The outlet J is controlled by any convenient valve h whichmay consist, as shown, of a disc adapted to abut on an annular seating2' around the outlet and having an operating stem 7' which extends fromone side of the disc and passes through a bore in the piston b the endof the stem remote from the disc being provided with a collar is againstwhich one side of the piston can abut for moving the disc away from itsseating. In addition .a tension spring m may be arranged as shown inassociation with the valve h to ensure full opening of the outlet I, oneend of this spring being attached to the end of the stem 1' remote fromthe valve, and the other end of the spring being attached to ananchorage n on the adjacent end of the accumulator a.

When the accumulator a is empty, the valve h is held on its seating i bythe piston 73 On setting the pump e in motion the liquid fuel suppliedby the pump to the accumulator (1 moves the piston b against the springor springs 0, weight or other opposing force acting on it. Meanwhile thevalve 71- is held closed by the pressure of the liquid. When the pistonb reaches or approaches the end of its movement it opens the valve h byacting on the collar 7c, the opening movement of the valve beingsupplemented by the spring m acting on the stem 7'. The pision 1) nowreturns under the action of the said opposing force causing the liquidcontent of the accumulator a to be discharged. At the same time the pumpe continues its discharge, and the combined discharges are such as willensure the ample supply of liquid fuel required by the nozzle or nozzlesg to start the prime mover.

The valve h having been opened as above described it will remain open solong as the pump e remains in action. On stopping the prime mover (andhence the pump e) the force acting on the accumulator piston b willcause the latter to re close the valve 72, and thereby put the theaccumulator in condition for a repetition of the above described actionwhen the prime mover is again set in motion.

In the modification illustrated in Figure 3 we employ for controllingthe flow of liquid fuel from the pump e to the nozzle or nozzles g, avalve h provided on or associated with one end of a spring loaded piston0 which is slidable within a hollow cylindrical body part p. The latteris adapted at one end to form a seating with which the Valve h cancooperate to close an opening whereby this end of the body part isconnected to an inlet pipe q communicating with the accumulator a andpump e, the diameter of the seating being considerably smaller than thediameter of the piston 0. At the other end of the body part p isarranged a connection for a drainage pipe 1" leading to a sump (notshown), and at one side of the body part adjacent to the inlet pipeconnection q is arranged a connection for as g. The piston o is providedwith a longitudi nal groove or passage t adapted to serve as a bypassbetween the outlet and drainage pipes s, 1".

When the system illustrated in Figure 3 is at rest, the piston ooccupiesits forward position under the action of its spring u. In this positionthe valve h co-operates with its seating to interrupt communicationbetween the inlet and outlet pipes q, 8. Also the outlet pipe scommunicates with the drainage pipe 1' through the piston bypass t,causing the outlet pipe s to be drained to the sump.

On starting up the pump e, the first effect is to charge the accumulatora against the action of its piston b, the latter being loaded by aspring or other convenient means. When a sufiicient pressure is attainedthe valve h is pushed off its seating sufficiently to allow liquid toflow into the body part 10 containing the valve controlling piston o andthence to the outlet pipe s, the accompanying movement of this pistoncausing the communication between the outlet and drainage pipes s, r tobe interrupted. When the liquid pressure acting on the full area of thefront end of the piston 0 becomes sufficient the piston is caused tocarry the valve It clear of its seating. An unrestricted communicationis thereby established between the inlet and outlet pipes q, s, and theaccumulator a is free to discharge.

In a preferred form of the system illustrated in Figure 3, the valve hand its controlling piston o are combined with the accumulator asexemplified in Figure 4. In this example the accumulator a contains aspring loaded piston 12, and has formed in one of its sides alongitudinal passage '2). At one end the passage 1; communil cates withan inlet pipe connection 10 through which liquid fuel from the pump canbe admitted to one end of the interior of the accumulator a. The otherend of the passage 11 communicates with a drainage pipe connection m,which also communicates with the interior of the accumulator a at theend remote from the inlet pipe connection w. At a position adjacent tothe drainage pipe connection a: the passage 11 is formed with acylindrical enlargement in which the valve-controlling piston o isslidably mounted, and which at the end nearest to the inlet pipeconnection w serves as a seating for the valve h. The piston o isseparate from and of larger diameter than valve h, and is loaded by aspring it which serves to hold one end of the piston in contact with thevalve, the latter being slidably supported in the passage 2; by a guideh of cruciform or other convenient cross section which permits free flowof liquid fuel through the adjacent part of the passage when the valveisopen. Ata position near the valve h the enlarged portion of the passagev communicates with an outlet pipe connection y through which liquidfuel can flow to the nozzle or nozzles. When the valve h is closed theoutlet pipe connection y is connected by a by-pass formed by alongitudinal groove or grooves t in the piston o to the drainage pipeconnection :0, this by-pass being closed when the valve is open.

The invention is not limited to the examples above described assubordinate constructional or mechanical details may be varied to suitdifferent requirements.

Having thus described our invention what We claim as new and desire tosecure by Letters Patent is:

1. A liquid fuel injection system having in combination a fuel pump, apart formed with a fuel delivery passage, an accumulator arranged to becharged with fuel by said pump when the latter is brought into action, astationary valve seating arranged between said fuel delivery passage andboth said pump and said accumulator, and a valve co-operating with saidseating to control flow of fuel to said passage from both said pump andsaid accumulator, said valve being arranged to be opened automaticallyin response to the delivery pressure of said pump when said accumulatorhas been charged, and thereafter to be retained by said pressure in theopen position so long as said pump remains in action, so that saiddelivery passage can be supplied with fuel first by said pump and saidaccumulator jointly, and then by said pump alone.

2. A liquid fuel injection system having in combination a fuel pump, apart formed with a fuel delivery passage, an accumulator comprising ahollow cylindrical body part arranged to be charged with fuel by saidpump when the latter is brought into action, and a loaded pistonslidable in said body part, a stationary valve seating arranged betweensaid fuel delivery passage and both said pump and said accumulator, anda valve co-operating with said seating to control fuel flow to saiddelivery passage from said pump, and also to said delivery passage fromsaid hollow cylindrical body part under the action of said piston, saidvalve being arranged to be opened automatically in response to the.delivery pressure of said pump when said accumulator has been charged,and thereafter to be retained by said pressure in the open position solong as said pump remains in action, so that said delivery passage canbe supplied with fuel first by said pump and said accumulator jointly,and then by said pump alone.

3. A liquid fuel injection system as claimed in claim 2 and having astem on which said valve is mounted and which passes through saidpiston, and a collar provided on said stem and actuable by said pistonfor opening said valve when said accumulator is charged.

4. A liquid fuel injection system as claimed in claim 2 and having astem on which said valve is mounted and which passes through saidpiston, a collar provided on said stem and actuable by said piston foropening said valve when said accumulator is charged, and a springattached to said stem for supplementing the opening movement of saidvalve.

5 A liquid fuel injection system as claimed in claim 2 and having aspring loaded piston of larger diameter than, and acting on, said valve,and a part having a second passage by which said delivery passage isconnectible tosaid pump and said accumulator under the control of saidvalve.

RICHARD JOSEPH IFIELD. ERNEST ANSLEY WATSON.

REFERENCES CITED The following references are of recor file of thispatent: d m the UNITED STATES PATENTS Number Name Date 1,502,739Munzinger July 29, 1924 2,197,772 Rockwell Apr. 23, 1940 2,426,319Meitzler May 26,1947

FOREIGN PATENTS Number Country Date 294,096 Great Britain i -192s

